Here's my update that may help a headlamp conversion, done only because I prefer the looks of the round lamp models, a bit of character.
All the parts were second hand and still not cheap.
The lamps came with the central mounting bar which is a little shorter than my later facelift 2011 model but they fit in the headstock mount as do all other items. The short Siamese wiring harness fits perfectly to the round lamps from the multi plug connector so no new harness needed.
The pics show the round lamps fitted with the later cowl and it looks too gappy and distant so I had to get the earlier cowl and fascia to be happy. The old cowl will not mount on the later fascia.
I've shown the parts side by side (old model items on the left) so you can compare with parts for sale as I found it tricky to distinguish. The early model uses 3 screws connecing fascia to cowl, the facelift one uses 4. Numbers on the items are;
Old cowl 2307575, new cowl A9700286
Old fascia 2307582, new fascia A9700287
I don't know if these are part numbers, I find Triumph part numbers a bit confusing and haven't yet found free parts manuals.
RS paints supplied the imperial purple paint, I haven't cut the laquer back yet so it looks a big rough.
Cost me about £280 including postage and paint. I got my bike for a good price so spent some of the savings.
Does anyone know what the blister is for on the top left of the early model cowl?